Dave
01-25-2006, 03:21 AM
Determining pH
pH is not constant in soil or water, but varies on a seasonal or even daily basis due to factors such as rainfall, biological growth within the soil, and temperature changes. Rather, a map of the pH level is a mosaic, varying according to soil crumb structure, on the surface of colloids, and at microsites. The pH also exhibits vertical gradients, tending to be more acidic in surface mulches and alkaline where evaporation, wormcasts, and capillary action draw bases up to the soil surface. It also varys on a macro level depending on factors such as slope, rocks, and vegetation type. Therefore the pH should be measured regularly and at various points within the land in question.
Methods of determining pH include:
Observation of predominant flora. Calcifuge plants (those that prefer an acidic soil) include Erica, Rhododendron and nearly all other Ericaceae species, many Betula (birch), Digitalis (foxgloves), gorse, and Scots Pine. Calcicole (lime loving) plants include Fraxinus (Ash), Honeysuckle (Lonicera), Buddleia, Cornus spp (dogwoods), Lilac(Syringa) and Clematis spp.
Observation of symptoms that might indicate acidic or alkaline conditions, such as occurrence of the plant diseases mentioned above or salinisation of alkaline soils. The house hydrangea (Hydrangea macrophylla) produces pink flowers at pH values of 6.8 or higher, and blue flowers at pH 6.0 or below.
Use of an inexpensive pH testing kit based on barium sulfate in powdered form, wherein a small sample of soil is mixed with water which changes colour according to the acidity/alkalinity.
Use of litmus paper. A small sample of soil is mixed with distilled water, into which a strip of litmus paper is inserted. If the soil is acid the paper turns red, if alkaline, blue.
Use of a commercially available electronic pH meter, in which a rod is inserted into moistened soil and measures the concentration of hydrogen ions.
pH is not constant in soil or water, but varies on a seasonal or even daily basis due to factors such as rainfall, biological growth within the soil, and temperature changes. Rather, a map of the pH level is a mosaic, varying according to soil crumb structure, on the surface of colloids, and at microsites. The pH also exhibits vertical gradients, tending to be more acidic in surface mulches and alkaline where evaporation, wormcasts, and capillary action draw bases up to the soil surface. It also varys on a macro level depending on factors such as slope, rocks, and vegetation type. Therefore the pH should be measured regularly and at various points within the land in question.
Methods of determining pH include:
Observation of predominant flora. Calcifuge plants (those that prefer an acidic soil) include Erica, Rhododendron and nearly all other Ericaceae species, many Betula (birch), Digitalis (foxgloves), gorse, and Scots Pine. Calcicole (lime loving) plants include Fraxinus (Ash), Honeysuckle (Lonicera), Buddleia, Cornus spp (dogwoods), Lilac(Syringa) and Clematis spp.
Observation of symptoms that might indicate acidic or alkaline conditions, such as occurrence of the plant diseases mentioned above or salinisation of alkaline soils. The house hydrangea (Hydrangea macrophylla) produces pink flowers at pH values of 6.8 or higher, and blue flowers at pH 6.0 or below.
Use of an inexpensive pH testing kit based on barium sulfate in powdered form, wherein a small sample of soil is mixed with water which changes colour according to the acidity/alkalinity.
Use of litmus paper. A small sample of soil is mixed with distilled water, into which a strip of litmus paper is inserted. If the soil is acid the paper turns red, if alkaline, blue.
Use of a commercially available electronic pH meter, in which a rod is inserted into moistened soil and measures the concentration of hydrogen ions.